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LMP2012: Offset calibration time

Thijs Ullrick
Prodigy 40 points
Part Number: LMP2012

For an application requiring a very low offset opamp we are considering the LMP2012QML.
One of the opamp’s electrical characteristics specified in the datasheet is the “offset calibration time”.
It is however not very clear to me how to interpret this “offset calibration time”.
Is this a one-time calibration delay at power-up or does this means that the opamp output is periodically not available due to required calibration?
It would be very helpful if someone could clarify this.

  • 0
    TI__Guru* 93105 points

    Hello Thijs,

    TI published an article about Auto Zero op amps such as the LMP2012QML in the 2Q 2005 Analog Applications Journal, "Auto-zero amplifiers ease the design of high-precision circuits." Figure 4 in the article shows the Auto Zero op amp circuit configuration in which it is evident that the upper op amp path is always active. The auto zero, or calibration path is continuously active as well. The offset calibration time is just how long it takes the amplifier to go through each calibration cycle. The switching associated with the calibration cycle produces mixer products, or noise spikes, as shown in the Figure 5 graph - Voltage Noise vs Frequency.

    You can find the TI article I referenced here:

    http://www.ti.com/lit/an/slyt204/slyt204.pdf

    Regards, Thomas

    Precision Amplifiers Applications Engineering

  • 0 in reply to Thomas Kuehl
    Prodigy 40 points

    Hello Thomas,

    Thanks for the clear and fast response.

    Regards,
    Thijs